The variation with temperature of the magnetizations of single crystals of Ni, Fe, and Fe+3 wt % Si are studied. New data for Fe and Fe(Si) is presented along with previously reported measurements for Ni. These data were obtained by means of the pyromagnetic effect at various applied fields and in the temperature range 4.2-140, 30, and 120°K for the Fe, Fe(Si), and Ni crystals, respectively. The observed departures from T 3/2 behavior are well described by spin-wave theory. Attempts to ascribe some of the measured variation of the magnetization to Stoner-type excitations or to variation of the moment per atom due to lattice expansion are mainly unsuccessful. The coefficients of the JT 3/2 term appropriate for zero spin-wave energy gap are C=7.5=t=0.2, 3.4=1=0.2, and 4.4±0.2X10-6 deg~3/ 2 for Ni, Fe, and Fe(Si), respectively. The coefficients of the T 6/2 term for zero gap are determined only for the Ni and Fe crystals as Z>= (1.5=1=0.2) X10~8 deg~6 /2 and (1±1)X10~9 deg~6 /2 , respectively. The measured variation of the spin-wave energy gap with applied field is consistent with the known g values of 2.19 and 2.09 for Ni and Fe. The magnitude of the gap at zero field is fully explained by the effects of magnetocrystalline anisotropy and magnetic-dipolar coupling. The values of the C and D coefficients are compared with results from independent experiments and are discussed in relation to theories of ferromagnetism in metals. OF FERROMETALS:Ni, Fe, AND Fe + 3% Si 2053 ARGYLE, CHARAP, AND PUGH

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The effect of neutron irradiation on copper-nickel alloys has been investigated by means of magnetic susceptibility measurements. The susceptibilities were measured by the Gouy method between 300°K and 2.0°K for a series of alloys ranging from 17.22 to 46.5 atomic percent nickel. It is shown that without superparamagnetism an unreasonable magnetic moment per nickel atom has to be assumed. This model is confirmed by irradiation studies in which samples were exposed to neutron fluxes at the Brookhaven reactor, ranging up to 2.2X10 19 neutrons/cm 2 while at 80°C, and the magnetic susceptibilities were found to increase following the irradiation. The increase was easily observable due to its strong temperature dependence, and was greatest for the samples with the highest nickel content and for samples exposed to the highest neutron fluxes. The susceptibilities of the alloys returned to their original values following an anneal in or above the temperature range where self-diffusion becomes important, while no changes in the susceptibilities were observed following anneals at lower temperatures. It is suggested that the coppernickel system is not a perfect random solid solution but tends toward segregation, and that the neutron irradiation enhances diffusion toward a true equilibrium at room temperature. This is in agreement with several other observations.

IBM's 360 and Early 370 Systems describes the creation of this remarkable system and the developments it spawned, including its successor, System/370. No new product offering has had greater impact on the computer industry than the IBM System/360. IBM's 360 and Early 370 Systems describes the creation of this remarkable system and the developments it spawned, including its successor, System/370. The authors tell how System/360's widely-copied architecture came into being and how IBM failed in an effort to replace it ten years later with a bold development effort called FS, the Future System. Along the way they detail the development of many computer innovations still in use, among them semiconductor memories, the cache, floppy disks, and Winchester disk files. They conclude by looking at issues involved in managing research and development and striving for product leadership. While numerous anecdotal and fragmentary accounts of System/360 and System/370 development exist, this is the first comprehensive account, a result of research into IBM records, published reports, and interviews with over a hundred participants. Covering the period from about 1960 to 1975, it highlights such important topics as the gamble on hybrid circuits, conception and achievement of a unified product line, memory and storage developments, software support, unique problems at the high end of the line, monolithic integrated circuit developments, and the trend toward terminal-oriented systems. System/360 was developed during the transition from discrete transistors to integrated circuits at the crucial time when the major source of IBM's revenue was changed from punched-card equipment to electronic computer systems. As the authors point out, the key to the system's success was compatibility among its many models. So important was this to customers that System/370 and its successors have remained compatible with System/360. Many companies in fact chose to develop and market their own 360-370 compatible systems. System/360 also spawned an entire industry dedicated to making plug-compatible products for attachment to it. The authors, all affiliated with IBM Research, are coauthors of IBM's Early Computers, a critically acclaimed technical history covering the period before 1960.

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